Arun Kilara

Enhancing the functionality of food proteins by enzymatic modification

Abstract Proteins are increasingly being utilized to perform functional roles in food formulations. Common food proteins possess good functional properties including solubility, gelation, emulsification and foaming. The functional properties of proteins are impaired near their pl (isoelectric point), as is the case in most acidic foods. Enzymatic modification of food proteins by controlled proteolysis can enhance their functional properties over a wide pH range, and other processing conditions. Choosing the right proteolytic enzyme, environmental conditions for hydrolysis and degree of hydrolysis is crucial for enhancing the functional properties of proteins. Understanding the molecular properties required for protein functionality and the development of strategies to achieve them are critical for developing and utilizing modified protein ingredients. Numerous reports on enhancing the functionality of food proteins by limited proteolysis have been published, some of which are reviewed in this article.

Peptides From Milk Proteins and Their Properties

This review has attempted to study the literature pertaining to peptides derived from milk proteins. Hydrolysis of milk proteins to generate peptides has been practiced for a long time and it was recognized early on in this process that the taste of hydrolyzates might hinder use of these products in food formulations. Modification of protein is necessary to form a more acceptable or utilizable product, to form a product that is less susceptible to deteriorative reactions and to form a product that is of higher nutritionall quality. Modifications may be achieved by a number of chemical and enzymatic means. This review has considered only enzymatic modification of dairy proteins. Modified proteins contain peptides and some of these peptides have been purified and their functionalities have been compared with unmodified proteins. This paper has examined the literature pertaining to improvement in functionality of enzyme-modified proteins. Improvements in solubility, emulsification, foaming and gelation were examined. There is limited information available on the sequence of the peptides necessary to improve the functional characteristics of proteins. Knowing the sequences of desirable functional peptides can lead to genetic alteration of proteins to improve functionality. Addition of synthetic peptides to intact proteins may be another way in which the functionality of proteins can be augmented. Some of the peptides in milk proteins are capable of affecting biological functions of an organism. These effects can be antimicrobial and probiotic, i.e., prevent the growth and proliferation of undesirable and pathogenic organisms, or they may promote the growth of desirable bacteria in the digestive tract of humans and animals. Peptides derived from milk protein have been shown to exert digestive and metabolic effects as well. They may also influence the immune system. These biological effects may play an important role in the development of medical foods that treat or mitigate the effects of diseases. Proteins are allergens and therefore it is possible that products derived from modification of proteins may also be allergens. The known literature about the allergenicity of peptides derived from milk proteins has been examined in this article. Last, but not the least, the taste attributes of peptides is also considered. Bitterness of hydrolyzates is a common occurrence and the origins of these bitter peptides and possible ways of mitigating this sensory defect has been discussed. Many of the peptides that enhance functionality and exert biological activity are likely to be bitter. Therefore, the bitter taste of hydrolysis products has to be dealt with in boosting the functional or nutraceutical aspects of foods containing these peptides. Analytical techniques for sequencing peptides have become more accessible and purification of peptides is commercially feasible. Computer based modeling techniques have aided the prediction of structures in these peptides. These advances, coupled with the advances in biotechnology, promise to revolutionize the future of nutraceutical and functional foods.

Effects of temperature on food proteins and its implications on functional properties

This article surveys the knowledge in the area of protein structure and chemistry of denaturation prior to an indepth review of the effects of heat on soy, milk, and egg proteins. It also reviews the methods available to assess denaturation of proteins. Protein denaturation is an ambiguous phenomenon and the consequences of denaturation on the functional properties of proteins is further confounded by this ambiguity. For each of the three food proteins, the known chemistry of individual proteins is reviewed followed by observations made on changes induced by heat in each protein group. Food proteins are not pure entities and purification and physicochemical characterization of various components of the food proteins have not been thoroughly investigated. Further, food is a complex milieu of water, fat, carbohydrate, vitamin, minerals, etc. along with proteins, and processing affects not only each individual component in the food but also the nature and intensity of intercomponent interactions in a food.

Clarification of Apple Juice

Consumer preference for a totally clear, shining apple juice has made clarified apple juice much more popular than unclarified natural apple juice. The production of clear apple juice requires the removal of suspended material and prevention of the development of turbidity after juice bottling. Freshly pressed juice contains suspended solids that are deliberately precipitated prior to filtration. This precipitation step is called clarification. Other measures often are taken to remove soluble materials that have the potential to form after-bottling hazes. These measures are often called fining. Fining methods, which can remove haze particles as well as soluble materials, are discussed in chapter 5. Table 4–1 lists materials that may cause turbidity in apple juice and their relative sizes.

Dairy processing and quality assurance

blbs005-chandan may 6, 2008 18:46 food5450groupb milk safety and quality assurance program dairy processing and quality assurance grocotts dairy processing and quality assurance saosey dairy beef quality assurance “instrumentation involved in quality dairy processing & quality assurance dairy processing and quality assurance researchgate quality management systems in dairy industry iieom dairy processing and quality assurance dockscafe food and dairy – food safety and quality assurance dairy processing and quality assurance maryroos compendium of lectures of dairy foods dairy processing (caft dairy processing worldwidehelpers california dairy quality assurance program fluid milk processing/testing for quality & safety course application of quality assurance programs in small dairy milk processing and quality management erpd guide to good dairy farming practice quality assurance for the indian dairy industry dairy processing improving quality xcelr “setting up mini milk processing plants at dairy farms for quality control of milk in the dairy industry idosi primary production and processing standard for dairy products milk processing and quality management safn position title: quality control department manager, dairy quality assurance from milking to processing steve zeng quality assurance for milking equipment ‘the dutch approach’ the basics of wisconsin dairy wisconsincheeseretail produced by the dairy products control bureau section vi. dairy conformance quality assurance program module on: dairy products quality and safety total quality assurance and hazard analysis critical cornell dairy foods extension program syllabu s – fluid the importance of quality milk bc dairy a manual of good practices in food quality management dairy processing plant product standardization and cdr brochure center for dairy research 9 application of biosensors for the quality assurance of a-a-20043c metric aa-20043d october 25, 2016 superseding dairy plant design and layout agrimoon handbook of organic food safety and quality toc dairy products and processing fgbt quality assurance programs for milk and dairy beef j.k imbedding haccp principles in dairy herd health and dairy product safety and security texas association of summary of requirements for michigan dairy processing plants

Lipase-catalyzed biochemical reactions in novel media : A review

Lipids in biological matter are mostly triacylglycerols (TAG). Lipolytic enzymes, primarily lipases, are indispensable for bioconversion of such lipids from one organism to another and within the organisms. In addition to their biological significance, lipases are very important in the field of food technology, nutritional and pharmaceutical sciences, chemical and detergent industries, and clinical medicine because of their ability to catalyze various reactions involving a wide range of substrates. Conventionally, lipases have been viewed as the biocatalysts for the hydrolysis of TAG (fats and oils) to free fatty acids, monoacylglycerols (MAG), diacylglycerols (DAG), and glycerol. The main advantages of lipase catalysis are selectivity, stereo-specificity, and mild reaction conditions. Despite these advantages and the fact that enzymatic splitting of fats for fatty acid production was described as early as in 1902, the lipase-catalyzed process has not replaced the commercial physicochemical process for th...

The use of immobilized enzymes in the food industry: A review

The production of high fructose corn syrups was greatly facilitated by the use of immobilized glucose isomerase. Similarly, in Japan, the fermentation industry proved its processing efficiency for amino acids through the use of immobilized amino acid acylase. This article discusses the use of soluble enzymes in the food industry followed by a section on the various available methods to immobilize enzymes. Once enzymes are immobilized, many of their operational parameters could be altered. Rationale for the determination of the effects of immobilization is provided. A relatively new concept is the use of a single matrix for immobilizing more than one enzyme. Immobilized multi-enzyme systems offer many attractive advantages; however, such a process also raises some interesting questions about kinetics. These questions and their suggested answers are discussed in the penultimate section. The major emphasis of this article is on the use of immobilized enzymes in the food industry. Two systems--amino acylase and glucose isomerase--have been demonstrated to be techno-economically feasible. Immobilization of other enzymes, such as glucoamylase, lactase, protease, and flavor modifying enzymes, has received some attention. The potential of these new systems are also discussed.

Enzyme reactions in reverse micelles

Abstract Enzyme reactions are important not only in life processes but also for the commercial production of various chemicals and foods. Many enzyme reactions of practical interest involve water-insoluble substrates and/or products. To improve the efficiencies of such reactions, one can exploit the system of reverse micelles to immobilize the enzymes and serve as a microheterogeneous reaction medium. Enzyme reactions in reverse micelles require lower reaction volumes, are not restricted by mass transfer considerations and are not subject to product-inhibition. Also, microbial contamination is minimized. The unique microenvironment of the enzyme allows for biocatalytic activity, stability and substrate specificity that is different and vastly improved as compared to that in the aqueous environment. However, to make reverse micellar enzymology a commercial reality, problems linked to product separation, enzyme recovery and re-use need to be addressed. This paper discusses various aspects of enzyme reactions in reverse micelles and other closely related media.

Whey and Lactose Fermentation

Previous chapters in this book have provided the necessary information required to define what whey is and what the compositional characteristics of this by-product are. Furthermore, it has also been shown that proteins can be isolated from this process ‘waste’ stream by methods that vary in their degree of sophistication. While these reviews delineate many successes, the problem of whey disposal is essentially one of lactose disposal, i.e. if the major constitutent of the dry matter in whey (lactose) can be converted or degraded, there will be no ‘whey problem’ on this earth. Coton (1979) reported that a total of 3 465 000 t of lactose was available from cheese manufacture in 1977 in the world. Of this, Western Europe generated 1 455 000 t (42%), Eastern Europe 931 000 t (26.9%), North America 822000 t (23.7%), South America 122, 000 t (3.5%), Australia 75 000 t (2.2%), and 60 000 t (1.7%) was attributed to other countries. No statistics are available for the utilization of lactose either by country or by end-use. Therefore the statistics are best guess or theoretical yields of available lactose. Zadow (1984) points out that the global market for lactose is inelastic and therefore increased production of lactose would result in a drastic decrease in prices. This economic reason serves as the justification for seeking alternative uses for lactose. It has also been suggested that two terms, ‘deproteinized whey’ and ‘permeate’, currently used interchangeably

ENZYMES EXOGENOUS TO MILK IN DAIRY TECHNOLOGY | Lipases

Enzymes added to milk or its components include those acting on lipids called lipases. Action of lipases on milk fat results in the release of free fatty acids, and mono- and diglycerides. Milk fat contains volatile, short-chain fatty acids, and the lipolyzed milk fat is used as flavoring material in cost- or calorie-reduced foods. This article describes the importance of lipases in generating enzyme-modified cheese and butter flavors using lipases and pregastric esterases. Free fatty acids react with amino acids and proteins to generate other desirable flavor compounds.